Reductive methylation of primary and secondary amines and amino acids by aqueous formaldehyde and zinc
作者:Renato A. da Silva、Idália H.S. Estevam、Lothar W. Bieber
DOI:10.1016/j.tetlet.2007.08.092
日期:2007.10
Amines can be methylated when treated with formaldehyde and zinc in aqueous medium. Selective mono- or dimethylation can be achieved by proper choice of pH, stoichiometry and reaction time. This method can also be applied for amino acids.
Stable-Isotope Dimethylation Labeling Combined with LC−ESI MS for Quantification of Amine-Containing Metabolites in Biological Samples
作者:Kevin Guo、Chengjie Ji、Liang Li
DOI:10.1021/ac0704356
日期:2007.11.1
was found that deuterium labeling causes an isotopeeffect on the elution of labeled amines on RPLC but has no effect on HILIC LC. However, 13C-dimethylation does not show any isotopeeffect on either RPLC or HILIC LC, indicating that 13C-labeling is a preferred approach for relative quantification of amine-containing metabolites in different samples. The isotopicallylabeled 35 amine-containing analogues
and to develop mass spectrometry methods for the identification of all possible methylated amino acids for future metabolomic studies. In this study, all N‐methyl and N,N‐dimethyl amino acids were synthesized by the methylation of α‐amino acids and characterized by a GC‐MS method. The methylated amino acids were derivatized with ethyl chloroformate and analyzed by GC‐MS under EI and methane/CI conditions
甲基化是生物系统中必不可少的代谢过程,对于活生物体中的几种生物反应而言都非常重要。已知甲基化化合物参与大多数身体功能,其中一些充当生物标记。从理论上讲,所有α-氨基酸都可以被甲基化,并且在大多数动植物样品中都可能遇到。但是分析数据,尤其是质谱数据,仅可用于少数甲基化氨基酸。因此,至关重要的是产生质谱数据并开发质谱方法以鉴定所有可能的甲基化氨基酸,以用于未来的代谢组学研究。在这项研究中,所有N-甲基和N,N二甲基氨基酸是通过α-氨基酸的甲基化合成的,并通过GC-MS方法进行了表征。甲基化的氨基酸用氯甲酸乙酯衍生化,并在EI和甲烷/ CI条件下通过GC-MS分析。N-甲基(1-18)和N,N-二甲基氨基酸(19-35)的氯甲酸乙酯衍生物的EI质谱显示出丰富的[M-COOC 2 H 5 ] +离子。由于[M-COOC 2 H]中的C 2 H 4,CO 2((CO 2 + C 2 H 4))的损失而产生的碎片离子5
Catalyst-Free One-Pot Reductive Alkylation of Primary and Secondary Amines and N,N-Dimethylation of Amino Acids Using Sodium Borohydride in 2,2,2-Trifluoroethanol
for the reductive alkylation of primary and secondary amines and N,N-dimethylation of amino acids is described using sodium borohydride as a reducing agent in 2,2,2- trifluoroethanol without use of a catalyst or any other additive. The solvent can be readily recovered from reaction products in excellent purity for direct reuse. reductive amination - 2,2,2-trifluoroethanol - sodium borohydride - reductive